Fig. 2.

Dynamics of the nuclear movement in 8-cell embryo. (A) Direction of the net movement recorded for nuclei starting the 8-cell stage in the apical or baso-central position. (B) Dynamics of the nuclear movement throughout the 8-cell stage. Each line represents a ratio of apical to basal nuclear distances plotted over time for the representative blastomeres (B1–5) showing different patterns of the nuclear movement. Images of the same blastomeres are presented in (C). (C) Time-lapse images of the representative blastomeres (B1–5) illustrating the movement of their nuclei (the apical/basal distance ratio, a quantitative measure of the movement, is presented in (B)). Time in the images is shown in hours and minutes (h:min) with the timepoint 0:00 in the beginning of the analysis. Initial positions of the nuclei are marked by a dashed white circle. Asterisks mark the apical surfaces of the blastomeres. Gap43-RFP, a membrane marker in red and histone H2B-GFP in green. Cartoons on the right side of the panel represent schematically the type of movement that is captured in the respective time-lapse images. (D) Frequency of symmetric and asymmetric divisions occurring in the cells with baso-central nuclei displaying different types of the net movement throughout the 8-cell cycle.